John R. Bolton, the U.S. ambassador to the United Nations, yesterday opposed a bill to withhold more than $130 million in funding to the world body unless it implements congressionally mandated reforms.

In his first appearance before Congress since becoming U.N. ambassador, Bolton warned Rep. Henry Hyde (R-Ill.), the powerful chairman of the House International Relations Committee who sponsored the bill, and other members of that panel that the legislation would undercut the president's authority to make foreign policy.

"I've been an executive branch official my entire public career and, for both constitutional and historical reasons, the executive branch appropriately has typically opposed automatic, nondiscretionary directions from all of you esteemed ladies and gentlemen," Bolton said. "That's our position," he added. "I support it emphatically.

Although Hyde's bill previously faced opposition from the State Department, the White House and the Senate, Republican staffers and U.N. officials said he is still hoping to use a parliamentary maneuver to force it through Congress before the end of the year.

But Bolton's remarks, coming from the administration's sharpest U.N. critic, were expected to deal a serious blow to those efforts. They also proved awkward for Hyde, who had invited Bolton to brief Congress on the outcome of a major U.N. summit earlier this month on poverty and reform.

Hyde nevertheless continued to make his case, saying "withholding dues is a wonderful way to get their attention" at the United Nations. He received little backing from colleagues, with the exception of Rep. Darrell Issa (R-Calif.), who told Bolton: "With all due respect to the executive branch, the purse strings do not belong to you."

Despite the disagreement, Bolton was enthusiastically embraced by Republicans who had vigorously supported his confirmation and was generally treated with deference by Democrats who had opposed it. Rep. Ileana Ros-Lehtinen (R-Fla.) said that Bolton has achieved "rock star" status among Republican congressional staff members who crowded into the committee chamber to hear him speak.

The reception contrasted with Bolton's bruising confirmation battle. Democrats and some Republicans in the Senate portrayed him as a bullying hard-liner incapable of patching up U.S. relations with the rest of the world. President Bush ultimately bypassed Democratic opposition, installing Bolton as ambassador on Aug. 1 in a recess appointment.

The change in tone reflected a recognition among some lawmakers that Bolton had demonstrated in his diplomatic debut that he could follow instructions from Washington and strike compromises. Some had feared that he would sabotage U.S. diplomacy at a U.N. summit attended by leaders from more than 150 countries.

Rep. Tom Lantos (Calif.), the ranking Democrat on the committee, challenged suggestions by some administration critics that Bolton's combative style had undermined U.S. diplomacy in New York. Instead, he blamed a small group of countries, including such close allies as Egypt and Pakistan and such rivals as Cuba, Venezuela and Iran, for trying to undercut U.S. policy and U.N. reforms. He said it is time for the Bush administration to "apply quid pro quo" diplomacy to secure support for U.S. aims.

The toughest criticism of Bolton came from Rep. Adam Schiff (D-Calif.). Schiff asked why Bolton had not been able to strike deals at the United Nations on an agreement to strengthen international efforts to curb the spread of biological and chemical weapons.

Bolton responded that U.S. negotiators had "tried very hard" to cut a deal, but had been opposed by countries that believe the United States, not rogue states pursuing nuclear arms, constitutes the greatest proliferation threat.

Bolton outlined two key priorities he said he will pursue in coming months. He said he will seek to strengthen U.N. efforts to contain international terrorism, by creating a larger role for the Security Council and by pressing for an anti-terrorism convention that would prohibit all acts of terrorism.

He also said he will seek to strike a fresh deal to increase oversight of the United Nations' books.

John R. Bolton said the House bill may impede U.S. policy.